The second half of the twentieth century has been marked by a dramatic influx of women into the paid labor force, but we are only beginning to understand the implications of this shift for women's health. This continuation study will investigate the effects of employment on women's physical health, focusing in particular on how this relationship may change as women move through midlife and how it may vary across four birth cohorts. Specific aims of the study are to: 1) examine the measurement properties and explore analytic techniques for a multiple item index of physical mobility limitations; 2) explore age and cohort changes in women's employment; 3) test whether there is age and/or cohort variation in the effect of employment on physical health; and 4) decompose each type of variation and investigate causes of each source of variation in the work-health relationship. The Mature and Young Women's cohorts of the National Longitudinal Surveys (NLS) will be used for these analyses. These data provide nationally representative samples of multiple birth cohorts of U.S. women over a fourteen to seventeen year period spanning the 1970's and 1980's. When combined, these two data sets provide one of the few nationally representative data with long-term longitudinal information on multiple cohorts of U.S. women. Analyses will use confirmatory factor analysis, fixed effects longitudinal regression models, and multilevel models in various stages of the analyses. Findings will contribute to basic research on health measurement and will further our understanding of social processes that may lead to earlier onset or progression of women's mobility limitations. Examining changes in the work-health relationship as women age and variations across birth cohorts also contributes to our understanding about how intersections of aging and social change may impact women's physical health.